U.S. patent application number 14/557727 was filed with the patent office on 2015-05-14 for rail wheel.
The applicant listed for this patent is KNORR-BREMSE SYSTEME FUR SCHIENENFAHRZEUGE GMBH. Invention is credited to Christian Mosbach, Xaver Wirth.
Application Number | 20150130202 14/557727 |
Document ID | / |
Family ID | 40521633 |
Filed Date | 2015-05-14 |
United States Patent
Application |
20150130202 |
Kind Code |
A1 |
Wirth; Xaver ; et
al. |
May 14, 2015 |
RAIL WHEEL
Abstract
A rail wheel with a wheel body and wheel brake discs connected
thereto with fastening elements on both sides is designed in such a
way that at least in the respective contact regions of the wheel
brake discs a mechanically and thermally highly resilient
intermediate layer is arranged on the wheel body
Inventors: |
Wirth; Xaver; (Ismaning,
DE) ; Mosbach; Christian; (Alling, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KNORR-BREMSE SYSTEME FUR SCHIENENFAHRZEUGE GMBH |
Munich |
|
DE |
|
|
Family ID: |
40521633 |
Appl. No.: |
14/557727 |
Filed: |
December 2, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12811131 |
Jun 29, 2010 |
8939488 |
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PCT/EP2008/010931 |
Dec 19, 2008 |
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14557727 |
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Current U.S.
Class: |
295/30 |
Current CPC
Class: |
F16D 65/12 20130101;
F16D 2065/1312 20130101; F16D 2065/138 20130101; F16D 2200/0017
20130101; F16D 2065/1392 20130101; F16D 65/124 20130101; B60B
17/0006 20130101 |
Class at
Publication: |
295/30 |
International
Class: |
F16D 65/12 20060101
F16D065/12; B60B 17/00 20060101 B60B017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 11, 2008 |
DE |
10 2008 003 923.3 |
Claims
1-18. (canceled)
19. A rail wheel comprising: a wheel body; and wheel brake disks
connected to the wheel body on both sides with fastening elements,
wherein a mechanically and thermally highly loadable intermediate
layer is provided between the wheel body and the wheel brake disks
at at least respective contact regions of the wheel brake disks,
wherein the intermediate layer is composed of a sheet of stainless
steel having a polished surface and having a greater strength than
the wheel body or a wheel web, and wherein the intermediate layer
slides relative to the respective wheel brake disk, and wherein the
intermediate layer is located in steps of the wheel web.
20. The rail wheel of claim 19, wherein sleeves are held in the
wheel web in bores for the passage of fastening elements for
securing the wheel brake disks.
21. The rail wheel of claim 20, wherein, the sleeves protrude on
both sides beyond the wheel web and passing through openings in the
intermediate layer, the outside diameter of the sleeves
approximately corresponding to the clear diameter of the openings
in the intermediate layer.
22. The rail wheel of claim 19, wherein, in the region of overlap
with the bores, the intermediate layer has collar-shaped flanges
which project into the bores, the outside diameter of the flanges
approximately corresponding to a clear diameter of the bores.
23. The rail wheel of claim 19, wherein, if the intermediate layer
is a circular ring portion, the circular ring portion has a contact
section on the outer circumference, forming a respective end
region, and a centrally arranged contact section on the inner
circumference, wherein the contact sections bearing against
boundaries of the steps.
24. The rail wheel of claim 19, further comprising sliding blocks
provided between the wheel brake disks and a wheel web and, in the
region of overlap with the sliding blocks, wherein the intermediate
layers have punched-out portions in which the sliding blocks
engage, the basic contour dimensions of the sliding blocks
approximately corresponding to a basic contour dimensions of the
associated punched-out portions.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a Continuation of U.S. patent
application Ser. No. 12/811,131, filed 29 Jun. 2010, which is a
U.S. nationalization under 35 U.S.C. .sctn.371 of International
Patent Application No. PCT/EP2008/010931, filed 19 Dec. 2008, which
claims the benefit of priority to German Patent Application No. 10
2008 003 923.3, filed 11 Jan. 2008. The disclosures set forth in
the referenced applications are incorporated herein by reference in
their entireties.
BACKGROUND
[0002] The invention relates to a rail wheel.
[0003] In the known rail wheels, the wheel brake disks connected to
the wheel body on both sides are fastened to the wheel body by a
plurality of fastening elements, primarily throughbolts,
distributed over the circumference.
[0004] In this case, the wheel brake disks bear with integrally
formed cooling ribs, centering and fastening eyes directly against
the wheel body, to be precise against a circumferential wheel web
which connects a wheel hub to an outer race.
[0005] However, considerable operationally induced problems arise
due to the direct contact of the wheel brake disks with the wheel
body.
[0006] For example, during a braking operation, as a result of the
axial temperature gradients which occur, considerable excessive
rises in the surface pressure occur radially on the outside of the
wheel brake disk between the wheel web and the contact regions. (If
the respective brake disk were not bolted to the wheel body, it
would assume the shape of a Belleville spring).
[0007] In addition, the annular wheel brake disks have the tendency
to deform in an opposed plate-like manner due to internal tensile
stresses in the frictional surfaces, which stresses occur due to
high thermal loading.
[0008] Excessive rises in the surface pressures in the radially
inner contact regions then occur in the cold state.
[0009] Due to a thermally induced "breathing" of the wheel brake
disk, i.e. a radial contraction and expansion at intervals, a
"frictional sliding" occurs in the contact regions during every
braking operation.
[0010] Due to the above-mentioned excessive rises in the surface
pressures, especially at high braking powers, scoring occurs
between the wheel brake disks and the wheel body in the region of
the contact regions or local plastic deformation occurs in the
wheel web, and this may lead in the long term to damage, such as
the formation of cracks, in the wheel.
SUMMARY
[0011] The invention is based on the object of developing a rail
wheel of the generic type in such a manner that an operationally
induced overstressing is prevented with structurally very simple
means and, as a result, the service life as a whole is
increased.
[0012] This object is achieved by a rail wheel as claimed.
[0013] Scoring phenomena and, therefore, wheel damage are avoided
by arranging a mechanically and thermally highly loadable
intermediate layer at least in the respective contact region
between the wheel brake disks and the wheel body.
[0014] The thermally induced radial deformations of the wheel brake
disk, which are referred to as "breathing" in the prior art and
occur during braking, are now ineffective, since the intermediate
layer acts as it were as a sliding layer on which either the wheel
brake disk correspondingly slides, when the intermediate layer is
held on the wheel body in a radially secured manner, or the
intermediate layer together with the connected wheel brake disk
moves in a sliding manner thereon relative to the wheel body.
[0015] The planar dimension of the intermediate layer is
expediently the same size or larger than the associated dimension
of the contact region of the wheel brake disks, and therefore a low
surface pressure is effective.
[0016] The above-mentioned scoring phenomena or plastic
deformations in the wheel web are, therefore, prevented, and
therefore the formation of cracks arising as a consequence thereof
is also effectively avoided.
[0017] This, of course, results in a significant increase in the
service life of the entire rail wheel and in a noticeable
improvement in operational reliability.
[0018] For this purpose, it is also expedient to produce the
intermediate layer from a metal sheet, the hardness of which is
significantly greater than the hardness or strength of the wheel
web.
[0019] A metal sheet made of stainless steel with polished
surfaces, which is customarily present in the form of rolled stock,
is ideally suited for this purpose, wherein the tensile strength of
a metal sheet of this type should be >1000 N/mm.sup.2 and the
thickness approximately 1 mm. However, in principle, other metal
sheet thicknesses are also usable.
[0020] According to at least one implementation, the intermediate
layers each consist of circular ring portions which are lined up in
a row next to one another in the circumferential direction.
[0021] In this case, circular ring portions of 30.degree.,
60.degree., 120.degree. or 180.degree. are conceivable. In
principle, of course, the intermediate layer may be designed as a
single-part sheet metal ring. The circular ring portions are
fastened in the radial direction in a form-fitting or frictionally
engaged manner. The form-fitting connection can take place either
at the wheel web or on the contact side of the wheel brake
disk.
[0022] By contrast, a frictional connection is achieved by
corresponding distortion by means of the bolted connection through
which the wheel brake disks are fastened to the wheel web or to the
wheel body.
[0023] Further implementation details of the invention are
characterized in the dependent claims.
BRIEF DESCRIPTION OF THE FIGURES
[0024] Exemplary embodiments of the invention are described below
with reference to the attached drawings, in which:
[0025] FIG. 1 shows a partial cutout of a rail wheel according to
the invention in a sectioned side view,
[0026] FIGS. 2 and 3 each show a further exemplary embodiment of
the invention in an enlarged partial cutout corresponding to FIG.
1,
[0027] FIG. 4 shows part of the rail wheel in a top view,
[0028] FIG. 5 shows a further exemplary embodiment of the invention
in an enlarged partial cutout in a sectional side view.
DETAILED DESCRIPTION
[0029] FIG. 1 illustrates a partial region of a rail wheel,
specifically of one of the regions in which wheel brake disks 2 are
connected on both sides to a wheel body 1.
[0030] In this case, a wheel web 3 of the wheel body 1, which wheel
web forms two circumferential, radially extending contact surfaces,
has a bore 14 through which a bolt 6 is guided, with which the
wheel brake disks 2 are fixedly connected to the wheel body 1.
[0031] Each bolt 6, of which a plurality is furthermore distributed
at an equal angular spacing on a circumferential circle, is guided
through a fastening eye 5 in the respective wheel brake disk 2, the
end side of said eye likewise forming a contact region in relation
to the wheel web 3, such as cooling ribs 4 of the wheel brake
disk.
[0032] An intermediate layer 7 assigned to each wheel brake disk 2
is arranged between the contact regions of the fastening eye 5 and
the cooling ribs 4 and the wheel web 3, and therefore the wheel web
3 and the contact regions of the wheel brake disk 2 bear against
said intermediate layer.
[0033] Said intermediate layers 7 are composed of a mechanically
and thermally highly loadable material, e.g., of a hard-rolled
metal sheet, the hardness or strength of which is greater than that
of the wheel web 3.
[0034] As can be seen particularly clearly in FIG. 4, the
intermediate layers 7 consist of circular ring portions which are
distributed uniformly over the circumference, wherein the number of
circular ring portions can vary. For example, for twelve bolts 6,
the same number of circular ring portions is provided, said
portions accordingly each enclosing an angle of 30.degree..
[0035] For radial securing purposes, the intermediate layers 7 may
be held in a form-fitting manner, to which end, in the example
shown in FIG. 1, the wheel web 3 has steps 8 in which the
intermediate layers 7 are located in a manner substantially secured
against displacement in the radial direction.
[0036] The intermediate layers 7 have corresponding openings for
the passage of the bolts 6.
[0037] In the example shown in FIG. 2 in which, as in FIGS. 3 and
5, an enlarged illustration in the contact region of the
intermediate layers 7 is reproduced; the radial securing takes
place in both directions, i.e., to the outside and to the inside,
by means of a sleeve 9, which is inserted into the bore 14 and is
held in an axially secured manner there. The sleeve 9 protrudes
over the wheel web 3 on both sides at least by the thickness of the
intermediate layers 7.
[0038] The outside diameter of the sleeve 9 approximately
corresponds to the clear diameter of a central recess in the
intermediate layer 7 such that the latter can easily be attached
and is held in a manner secured against lateral displacement.
[0039] In the variant embodiments according to FIGS. 1 and 2, the
intermediate layers 7 are, therefore, locked on the wheel web 3. By
means of the visible extensive contact of the intermediate layers 7
with the wheel web 3, the outside radius of which is determined by
the radial width of the cooling ribs 4 which virtually form outer
contact regions, the production of significant temperature
differences between the metal sheet and wheel web are avoided and
therefore so too are thermally induced distortions of the
intermediate metal sheets in relation to the wheel. The metal
sheets do not slide on the wheel web.
[0040] By contrast, the wheel brake disk 2 which is supported on
the respective intermediate layer slides in the radial direction on
the intermediate layer 7 in the event of a thermally induced
changing shape such that scoring or damage of the wheel web is
prevented.
[0041] In the sense mentioned above, the intermediate layers 7 are
also locked on the wheel web 3 in the example shown in FIG. 5.
[0042] For this purpose, the intermediate layers 7 have flanges 13
in the region of the bores 14 in the wheel web 3, the flanges being
in the form of collars and projecting into the bore 14, and
corresponding in the outside diameter thereof approximately to the
clear diameter of the bore 14 such that radial securing in both
directions is ensured.
[0043] FIG. 3 illustrates a further example of fixing the
intermediate layers 7.
[0044] Here, the wheel brake disk 2, in the contact regions thereof
which face the wheel web 3, has steps 10 in each of which one of
the intermediate layers 7 is located and secured radially.
[0045] During a temperature-induced expansion and contraction of
the wheel brake disks 2, in the radial direction, the respective
intermediate layer 7 moves at the same time by the same amount such
that the intermediate layers 7 virtually slide on the wheel web
3.
[0046] As can be seen in FIG. 4, there is a further type of radial
fixing of the intermediate layers 7 in that punched-out portions
are made in said intermediate layers in the region of overlap with
sliding blocks 11, which are arranged between the wheel web 3 and
the wheel brake disks 2, said punched-out portions corresponding in
the basic contour dimensions thereof to the sliding blocks 11,
wherein the sliding blocks 11 pass through the associated
punched-out portions, thus resulting in form-fitting positional
fixing on the wheel web 3.
[0047] Since temperature differences occur between the wheel brake
disk 2 and the intermediate layer 7 during each braking operation,
the intermediate layer 7 is designed in such a manner that
differences in curvature do not result in any distortion.
[0048] The intermediate layer 7 is configured such that the
intermediate layer 7 is provided on the outer and inner borders
with contact portions 12 which bear against the associated edges of
the steps 8, 10 (FIG. 4).
[0049] In principle, a single-part intermediate layer in the form
of a ring is capable of functioning. However, due to the large
diameter of the wheel brake disks 2 for rail wheels, it is
substantially more cost effective to use circular ring portions,
wherein the latter are punched or cut by laser beam or water
jet.
[0050] In the example shown in FIG. 4, 60.degree. circular ring
portions are selected, and each intermediate layer 7 is provided on
the outer border with two contact portions 12 and on the inner
border with one contact portion 12 which is located in the center
while the two outer contact portions are arranged, with respect to
the length, in the outer border regions, thus resulting in
three-point contact by means of which, as mentioned, distortion in
the event of differences in curvature is prevented.
LIST OF REFERENCE NUMBERS
[0051] 1 Wheel body [0052] 2 Wheel brake disk [0053] 3 Wheel web
[0054] 4 Cooling rib [0055] 5 Fastening eye [0056] 6 Bolt [0057] 7
Intermediate layer [0058] 8 Step [0059] 9 Sleeve [0060] 10 Step
[0061] 11 Sliding block [0062] 12 Contact portion [0063] 13 Flange
[0064] 14 Bore
* * * * *